Spinal fixation devices are used in orthopedic surgery to align or repair a relationship between vertebrae. Such devices may include one or more rods that are attached to vertebrae by screws, bolts, hooks, or other anchoring devices. The rods may have a contour that is pre-formed according to the properties of the implantation site. Alternatively, the contour of the rods may be created during surgery to conform to the implantation site. The rods hold the vertebrae in a desired spatial relationship until healing or spinal fusion has taken place, or for some other desired period of time.
In cases where multiple rods are used, cross connectors may be used to provide additional stability and maintain the rods in a desired position. One known type of cross connector is a rod having clamps formed on opposite ends for mating with spinal rods. Typically, such a cross connector employs two set screws, or other such locking mechanisms to fix each end of the cross connector to the spinal rods. Telescopic and other length adjustable cross connectors are also known, which may include a third set screw or other locking mechanism to fix the length of the cross connector.
U.S. Pat. No. 5,330,473 discloses a cross connector that employs a single bolt. The cross connector includes a lower saddle and an upper saddle. The lower saddle includes arcuate channels to receive spinal rods. The upper saddle is configured to mate with the lower saddle and define upper portions of the arcuate channels. The upper channel is locked in place with the bolt.
U.S. Patent Application Publication 2006/0058789 discloses a cross connector that employs a single locking mechanism. When the locking mechanism is tightened, it engages sliding or pivoting “shoes” which lock the cross connector in place with respect to a pair of spinal rods.